Hello. If I have an xBee connected on pin 0 and 1 and I am using it on API mode, can I use the serial port also to write on my computer screen for debug? I don't think what I write in screen is send on the wireless becuse it is not in api format. But what do you think about? Do you think packets for the monitor may interfere with radio transmission or not?Thanks

I think you'll find it will interfere - just because it's not a certain format doesn't mean the Xbee won't see it and try to interpret as something usable... so why not just use different pins for the Xbee comms and avoid any possible headaches...?

Not absolutely sure that it's 100% safe (it may be with AP=2), but I've done this and never noticed a problem. Use AP=2 if you can and as long as you don't send 0x7E in a debug message, the XBee should ignore it. You will see XBee API traffic on the monitor as gobbledegook, but you can ignore that!